Hydrometer



FIG. 1 is a top perspective view of a hydrometer showing my new design;

FIG. 2 is a side elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a side elevational view of another embodiment of my new design of FIGS. 1-5 with a stem sheath added thereto;

FIG. 7 is a bottom plan view of FIG. 6. 

The ornamental design for a hydrometer, substantially as shown and described. 